19-20 years ago I boarded my cat a couple of times and decided later that it must have been awful for him, but I had no choice.
since then I always leave my cats at home and look for someone to stay here while I am gone. if I can't find anyone to stay, I try to go with a neighbor so it won't be much trouble for them to pop in 2-3 times a day and I always pay them, and I only choose people I know and trust. (obviously, leaving them with my house key lol).
i'd be afraid to leave my cats at someone else's house even though they'd probably be okay. if they had an accident (although they never do here anymore) i'd feel terrible, if they ran away i'd feel terrible, etc. etc.
if you can't find someone to stay at your place, hire a professional sitter to come in. I kept a friend's cat once (only for a couple of days) and I felt horrible for the kitty. she hid and wouldn't eat and only came out from under the bed to use the litter box. I had two cats but they didn't bother her at all, she was just terrified to be away from home and peed on her owner when he came to get her.
even if you hire a professional, leave a very
detailed checklist of things for them to do (complete with emergency numbers), don't assume anything: if you don't tell them specifically to do something, it probably won't get done. if you are very particular, write down exactly how you want something done. something I think is a no-brainer is, "rinse the empty food cans and throw them away in a trash receptacle the cats can't get into or better yet, take them with you when you leave and throw them away." same thing with litter. specify how often you want it scooped and leave poop bags so that the clumps (or whatever you use) can be thrown away immediately and won't leave your house nice and ripe for you to come home to. if you want their dishes washed after every meal, say so. tell them how often you want the water changed.